Search Publications
Nuclear Activity in the Low-metallicity Dwarf Galaxy SDSS J0944-0038 : A Glimpse into the Primordial Universe
Nyland, Kristina; Canalizo, Gabriela; Satyapal, Shobita +11 more
Local low-metallicity dwarf galaxies are relics of the early universe and are thought to hold clues into the origins of supermassive black holes. While recent studies are uncovering a growing population of active galactic nuclei (AGNs) in dwarf galaxies, the vast majority reside in galaxies with solar or supersolar metallicities and stellar masses…
The intense production of silicates during the final AGB phases of intermediate mass stars
Dell'Agli, F.; Ventura, P.; Fabrizio, M. +7 more
Context. The formation of silicates in circumstellar envelopes of stars evolving through the asymptotic giant branch (AGB) is still highly debated given the uncertainties affecting stellar evolution modelling, the description of the dust formation process, and the capability of silicate grains to accelerate stellar outflows via radiation pressure.…
Using the Gaia Excess Uncertainty as a Proxy for Stellar Variability and Age
Barber, Madyson G.; Mann, Andrew W.
Stars are known to be more active when they are young, resulting in a strong correlation between age and photometric variability. The amplitude variation between stars of a given age is large, but the age-variability relation becomes strong over large groups of stars. We explore this relation using the excess photometric uncertainty in Gaia photom…
Innovative technique for separating proton core, proton beam, and alpha particles in solar wind 3D velocity distribution functions
Fedorov, A.; Livi, S.; Louarn, P. +10 more
Context. The identification of proton core, proton beam, and alpha particles in solar wind ion measurements is usually performed by applying specific fitting procedures to the particle energy spectra. In many cases, this turns out to be a challenging task due to the overlapping of the curves.
Aims: We propose an alternative approach based on …
A rotating white dwarf shows different compositions on its opposite faces
Kulkarni, S. R.; Vennes, Stéphane; Hermes, J. J. +35 more
White dwarfs, the extremely dense remnants left behind by most stars after their death, are characterized by a mass comparable to that of the Sun compressed into the size of an Earth-like planet. In the resulting strong gravity, heavy elements sink towards the centre and the upper layer of the atmosphere contains only the lightest element present,…
A multiwavelength study of multiple spectral component jets in AGN: testing the IC/CMB model for the large-scale-jet X-ray emission
Georganopoulos, Markos; Breiding, Peter; Meyer, Eileen T. +3 more
Over ~150 resolved, kpc-scale X-ray jets hosted by active galactic nuclei have been discovered with the Chandra X-ray Observatory. A significant fraction of these jets have an X-ray spectrum either too high in flux or too hard to be consistent with the high-energy extension of the radio-to-optical synchrotron spectrum, a subtype we identify as Mul…
Slow Solar Wind Connection Science during Solar Orbiter's First Close Perihelion Passage
D'Amicis, Raffaella; Teriaca, Luca; Hirzberger, Johann +76 more
The Slow Solar Wind Connection Solar Orbiter Observing Plan (Slow Wind SOOP) was developed to utilize the extensive suite of remote-sensing and in situ instruments on board the ESA/NASA Solar Orbiter mission to answer significant outstanding questions regarding the origin and formation of the slow solar wind. The Slow Wind SOOP was designed to lin…
Blue Large-Amplitude Pulsators and Other Short-Period Variable Stars in the OGLE-IV Galactic Disk Fields
Soszyński, I.; Udalski, A.; Szymański, M. K. +12 more
Blue Large-Amplitude Pulsators (BLAPs) form a mysterious class of variable stars with typical periods of tens of minutes and amplitudes above 0.1 mag. In this work, we present results of a variability search focused on timescales shorter than 1 h, conducted in OGLE-IV Galactic disk fields containing about 1.1 billion stellar sources down to I≈20 m…
UOCS-IX. AstroSat/UVIT Study of the Open Cluster NGC 2818: Blue Stragglers, Yellow Stragglers, Planetary Nebula, and their Membership
Rao, N. Kameswara; Subramaniam, Annapurni; Rani, Sharmila +1 more
We present the first far-UV (FUV) imaging results of the intermediate-age Galactic open cluster NGC 2818 that has a planetary nebula (PN) within the field using images taken from the Ultra Violet Imaging Telescope (UVIT) aboard AstroSat. We identify cluster members by combining UVIT-detected sources with Gaia EDR3 data. We detect four bright and h…
A search for transit timing variations within the exomoon corridor using Kepler data
Kipping, David; Yahalomi, Daniel A.
An exomoon will produce transit timing variations (TTVs) upon the parent planet and their undersampled nature causes half of such TTVs to manifest within a frequency range of two to four cycles, irrespective of exomoon demographics. Here, we search through published Kepler TTV data for such signals, applying a battery of significance and robustnes…